Alterations of left ventricular myocardial strain in obese children

Obesity may have implications in the myocardial structural change, which may contribute to mechanical consequences. Using 2D speckle echocardiography, we looked for myocardial changes and investigated their relation to obesity, inflammation, insulin resistance and physical capacity in children with isolated obesity. Standard echocardiography and 2D strain were prospectively performed in obese children and compared them with age- and sex-matched controls. Z-score body mass index (BMI Z-score), ultra-sensitive C reactive protein, indices of insulin resistance (HOMA-IR) and metabolic stress test were assessed in obese children. Thirty-two consecutive obese patients [age: 12.8 (8-17) years; 15 males; BMI Z-score: 5.8 [2.05-8.6)] were compared with 32 controls. Longitudinal strain and circumferential strain were significantly lower in the obese group (respectively -18.0 ± 2.4% vs. -20.6 ± 2.5%; P = 0.0001 and -18.2 ± 3.5% vs. -20.1 ± 2.3%; P = 0.013), while radial strain did not differ. Longitudinal strain was correlated with HOMA-IR (Pearson's rho = -0.39) and with the exercise capacity (Pearson's rho = 0.62). In the multivariate analysis, after adjusting for age, the mean arterial pressure and left ventricular (LV) mass, the BMI Z-score remained independently related to the longitudinal and circumferential strain. Childhood obesity may be associated with an early alteration of the longitudinal and circumferential LV strain. These findings have potentially significant clinical implications for the outcomes and follow-up of obese children meriting further studies.